It is a little bit tighter. The Werks engines are not very tight from new. With the medium resize, if they are broke in properly will last quite a long time. The light tightness is closer to the new Werks tightness. and will require less break in but will not last as long as the medium.

If the engine is in good shape and you can spend the time to break it in the medium gives the best results. usually going 4+ gallons. the light usually go about 2-4 depending on the engine. BUt a lot of guys like the light because there is less break in and they just want to get a couple more gallons out of it before they retire it.

Thanks,
Lance
RcRenew